The present invention is concerned with preventing or prolonging the expiration of gases contained in various liquids, including carbonated beverages. Conventional containers seek to maintain or limit the escape of gases from carbonated beverages or other gas-pressured liquids by providing a tight seal which prevents leakage from the container. This does not result in limiting the volume of release of gases from the liquid since the volume of unpressurized (or less pressurized) air inside the container increases each time that a further volume of liquid is dispensed from the container. As the volume of the liquid is diminished, the volume of unpressurized air increases. The result is that the gas in the liquid escapes into the unpressurized airspace as it moves from an area of higher pressure to one of lower pressure. This occurs until the gas achieves equal pressure throughout the container. Over time, the gas content in the liquid reduces to a point at which the liquid has lost all its effervescent character, at which point it is considered to have gone “flat”.
A number of container designs have been proposed in the prior art for the purpose of prolonging the amount of time it takes for a carbonated beverage to go flat.
U.S. Pat. No. 4,723,670 disclose a hand operated pump device installed on an otherwise conventional soda bottle to enable re-pressurization of the bottle after some of the beverage has been consumed from same in order to help maintain the carbonated state of the beverage.
U.S. Pat. No. 6,484,897 discloses a variable volume container which can be reduced in size as the liquid is depleted therefrom in order to reduce the available airspace into which the carbon dioxide from a carbonated beverage can escape.
U.S. Pat. No. 3,235,138, with reference to FIG. 4 thereof, discloses another approach for maintaining a carbonated state of a beverage by equipping a spigot-drained container with a free riding plate that is biased downward against the upper surface of its carbonated liquid content by a resilient sponge material contained in an impervious flexible bag sealed to the upper end of the container above the free riding plate, whereby the plate is biased downward against the surface of the liquid to maintain pressurization of same.
U.S. Pat. No. 6,290,105 and U.S. Patent Application Publication US2011/0290826 disclose containers for preserving wine from an uncorked bottle. IN each reference, a sliding piston is forced down against the surface of the container's liquid content in order to reduce the effective volume of the container and eliminate any airspace within same to prevent exposure of the wine to atmospheric air. Another piston-equipped container for wine preservation is disclosed in U.S. Patent Application Publication US2011/0114592.
Other piston-equipped containers used for various purposes include those disclosed in U.S. Pat. Nos. 1,630,899, 3,786,966, 4,796,785 3,784,051, DE9319341, DE102006004500, and WO2010124330.
However, there remains room for improved or alternative options in the field concerned, and Applicant discloses herein a new container design that incorporates a unique combination of features neither seen in, nor suggested by, the forgoing prior art.